Impact of cyclooxygenase-2 expression on the survival of glioblastoma multiforme

Abstract

12505 Background: Expression of cyclooxygenase-2 (COX-2) protein in glioma patients increased proportionally to the pathologic grade. The extent of COX-2 expression is reported to have an inverse relation to survival rate in glioblastoma multiforme (GBM) patients, but the degree of COX-2 expression in the GBM specimens is variable from study to study. In order to evaluate the degree of COX-2 expression and its effect on survival in GBM patients, we conducted this study. Methods: Between 1997 and 2006, thirty consecutive patients of GBM who were treated with surgery and postoperative radiotherapy (range : 44 ∼ 65.1 Gy, median : 61.2 Gy) were included after exclusion of 3 patients who discontinued radiotherapy before 40 Gy due to mentality deterioration. Expression of COX-2 protein on surgical specimen was examined by immunohistochemistry. Survival analysis and verification were performed in respect to sex, age, resection extent, radiotherapy dose, and degree of COX-2 expression with Kaplan-Meier method and log rank test. Results: The median length of follow up was 13.25 months (6 ∼ 83 months). COX-2 was stained in all patients and COX-2 positives over 75% of tumor cells were found in 24 patients: positive in less than 25% of tumor cells, N = 3 (10.0%); 25 to 50%, 1 (3.3%); 50 to 75%, 2 (6.7%); 75 to 100%, 24 (80.0%). Median survival and 2-year survival rate were 13.5 months and 17.5%, respectively. The survival rate was influenced significantly by the degree of resection (tumor removal by 50% or more) and radiotherapy dose (60 Gy or greater) (p < 0.05). Median survivals of patients with COX- 2 positive in either more than 75% of tumor cells or at most 75% of tumor cells were 13.0 and 15.5 months, respectively (p>0.05), and the 2- year survivals of them were 13.3 and 33.3%, respectively (p>0.05). Conclusions: Eighty percent of the GBM patients were COX-2 positive in more than 75% of their tumor cells. The degree of COX-2 expression in the GBM patients had not a significant impact on survival, but the high positive rate of COX-2 in GBM could be a potential selective target for treatment. No significant financial relationships to disclose.